Try to add an ID to your RG element, example : myrg
Then add a HTML element in your page, it must be visible but you cs’ set it 1px width / 1mx height a d put it at the x=0 and y=-1 position on your page.
In the html element, add the following to add the css rule to center the RG :
<style>
#myrg {
display: flex;
flex-wrap: wrap;
justify-content: center;
}
</style>
Give a try and let us know.